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1.
Brain Sci ; 12(12)2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36552173

RESUMEN

INTRODUCTION: Individual real-time functional magnetic resonance imaging neurofeedback (rtfMRI NF) might be a promising adjuvant in treating depressive symptoms. Further studies showed functional variations and connectivity-related changes in the dorsolateral prefrontal cortex (dlPFC) and the insular cortex. OBJECTIVES: The aim of this pilot study was to investigate whether individualized connectivity-based rtfMRI NF training can improve symptoms in depressed patients as an adjunct to a psychotherapeutic programme. The novel strategy chosen for this was to increase connectivity between individualized regions of interest, namely the insula and the dlPFC. METHODS: Sixteen patients diagnosed with major depressive disorder (MDD, ICD-10) and 19 matched healthy controls (HC) participated in a rtfMRI NF training consisting of two sessions with three runs each, within an interval of one week. RtfMRI NF was applied during a sequence of negative emotional pictures to modulate the connectivity between the dlPFC and the insula. The MDD REAL group was divided into a Responder and a Non-Responder group. Patients with an increased connectivity during the second NF session or during both the first and the second NF session were identified as "MDD REAL Responder" (N = 6). Patients that did not show any increase in connectivity and/or a decreased connectivity were identified as "MDD REAL Non-Responder" (N = 7). RESULTS: Before the rtfMRI sessions, patients with MDD showed higher neural activation levels in ventromedial PFC and the insula than HC; by contrast, HC revealed increased hemodynamic activity in visual processing areas (primary visual cortex and visual association cortex) compared to patients with MDD. The comparison of hemodynamic responses during the first compared to during the last NF session demonstrated significantly increased BOLD-activation in the medial orbitofrontal cortex (mOFC) in patients and HC, and additionally in the lateral OFC in patients with MDD. These findings were particularly due to the MDD Responder group, as the MDD Non-Responder group showed no increase in this region during the last NF run. There was a decrease of neural activation in emotional processing brain regions in both groups in the last NF run compared to the first: HC showed differences in the insula, parahippocampal gyrus, basal ganglia, and cingulate gyrus. Patients with MDD demonstrated deceased responses in the parahippocampal gyrus. There was no significant reduction of BDI scores after NF training in patients. CONCLUSIONS: Increased neural activation in the insula and vmPFC in MDD suggests an increased emotional reaction in patients with MDD. The activation of the mOFC could be associated with improved control-strategies and association-learning processes. The increased lOFC activation could indicate a stronger sensitivity to failed NF attempts in MDD. A stronger involvement of visual processing areas in HC may indicate better adaptation to negative emotional stimuli after repeated presentation. Overall, the rtfMRI NF had an impact on neurobiological mechanisms, but not on psychometric measures in patients with MDD.

2.
Animals (Basel) ; 11(10)2021 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-34679815

RESUMEN

Knowledge about the distribution of Anaplasma spp. in small ruminants from Germany is limited. Therefore, serum samples were examined from 71 small ruminant flocks (2731 sheep, 447 goats) located in the five German federal states: Schleswig-Holstein (SH), Lower Saxony (LS), North Rhine-Westphalia (NRW), Baden-Wuerttemberg (BW) and Bavaria (BAV). Antibodies to Anaplasma spp. were determined by a cELISA based on the MSP5 antigen. A risk factor analysis at animal and flock level was also performed. Antibodies to Anaplasma spp. were detected in 70/71 flocks without significant difference in the intra-flock prevalence (IFP) between the federal states. The mean antibody levels from sheep were significantly lower in northern Germany (LS, SH) compared to west (NRW) and south Germany (BW, BAV). Sheep had a 2.5-fold higher risk of being seropositive than goats. Females and older animals (>2 years) were more likely to have antibodies to Anaplasma spp. in one third and one quarter of cases, respectively. Flocks used for landscape conservation had a five times higher risk of acquiring an IFP greater than 20%. Cats and dogs on the farms increased the probability for small ruminant flocks to have an IFP of above 20% 10-fold and 166-fold, respectively. Further studies are necessary to assess the impact of Anaplasma species on the health of small ruminants in Germany.

3.
Front Vet Sci ; 8: 623786, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33644150

RESUMEN

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Inhalation of contaminated dust particles or aerosols originating from animals (esp. small ruminants) is the main source of human infection. Hence, an active early warning system for Q fever in German small ruminant livestock was conceptualized to prevent human infections. First, we describe the best practice for establishing this system before evaluating its feasibility, as the combination of both evokes conflicts. Vaginal swabs from all husbandry systems with a focus on reproductive females should pooled and investigated by PCR to detect C. burnetii-shedding animals. Multistage risk-based sampling shall be carried out at the flock level and within-flock level. At the flock level, all flocks that are at risk to transmit the pathogen to the public must be sampled. At the within-flock level, all primi- and multiparous females after lambing must be tested in order to increase the probability of identifying a positive herd. Sampling should be performed during the main lambing period and before migration in residential areas. Furthermore, individual animals should be tested before migration or exhibition to ensure a negative status. If a flock tests positive in at least one individual sample, then flock-specific preventive measures should be implemented. This approach implies huge financial costs (sample testing, action/control measures). Hence, taking the step to develop more feasible and affordable preventive measures, e.g., vaccinating small ruminant flocks, should replace testing wherever justifiable.

4.
One Health ; 12: 100227, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33732862

RESUMEN

Tick-borne encephalitis virus (TBEV) is one of the most common zoonotic vector-borne infections in Europe. An appropriate awareness is crucial to react quickly and efficiently to protect humans from this pathogen. From winter 2017 until spring 2018 serum samples were collected from 71 small ruminant flocks (3174 animals) in five German federal states. The sera were examined for TBEV antibodies by ELISA and serum neutralization test. In the TBEV risk areas, there was a coincidence in 14 districts between seropositive small ruminants and the occurrence of human TBE cases in 2017. In eight districts, the TBEV infection could not be detected in small ruminants although human cases were reported. In contrast, in five districts, small ruminants tested TBEV seropositive without notified human TBE cases in 2017. A changing pattern of TBEV circulation in the environment was observed by the absence of antibodies in a defined high-risk area. In the non-TBE risk areas, seropositive small ruminants were found in five districts. In two districts with a low human incidence the infection was missed by the small ruminant sentinels. An intra-herd prevalence of 12.5% was determined in a goat flock in the non-TBE risk area in 2017, two years prior the first autochthone human case was reported. All sheep and goats in this flock were examined for TBEV antibodies for three years. Individual follow-up of twelve small ruminants was possible and revealed mostly a short lifespan of TBEV antibodies of less than one year. The probability to identify TBEV seropositive sheep flocks was enhanced in flocks kept for landscape conservation or which were shepherded (p < 0.05). Our preliminary observations clearly demonstrated the successful utilization of small ruminants as sentinel animals for TBEV.

5.
Vaccine ; 39(10): 1499-1507, 2021 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-33558108

RESUMEN

Qfever is a zoonotic disease caused by the bacterium Coxiella burnetii; Coxiella-infected ruminants are the main reservoir shedding the pathogen during abortion or parturition through birth products. Germany has a long history of small-scale Q fever epidemics in the human population mostly associated with lambing sheep. Therefore, fast and efficient control measures are essentially required to prevent transmission from infected sheep flocks to humans. In our present study, three sheep flocks were vaccinated with an inactivated C.burnetii phase I vaccine after a field infection with C.burnetii was diagnosed. Serum samples and vaginal swabs were collected at different time points to evaluate the extent of the outbreak and the consequences of the vaccination. The serum samples were examined by phase-specific IgG phase I and phase II ELISAs and a commercial ELISA, simultaneously detecting both phase variations. Moreover, vaginal swabs were analysed by qPCR. The fourth flock with no Q fever history and non-vaccinated animals were used as a control group to evaluate the phase-specific ELISAs. The inactivated C.burnetii phase I vaccine induced an IgG phase II response and boosted the humoral immune reaction against natural pre-infections. Furthermore, the longevity of vaccine-induced antibodies seems to depend on previous infections. Around 16 months after primary vaccination, mainly IgG phase I antibodies were detectable. Vaccination did not prevent shedding at the next lambing season. Most interestingly, the phase-specific ELISAs revealed more C.burnetii positive animals than the blended ELISA-Assay. Taken together, phase-specific ELISAs are suitable tools to provide insights into natural- or vaccine-induced humoral immune responses to C.burnetii in sheep.


Asunto(s)
Coxiella burnetii , Fiebre Q , Enfermedades de las Ovejas , Animales , Femenino , Alemania , Cabras , Inmunidad Humoral , Embarazo , Fiebre Q/prevención & control , Fiebre Q/veterinaria , Ovinos , Enfermedades de las Ovejas/prevención & control , Vacunación/veterinaria
6.
J Med Genet ; 58(7): 484-494, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-32820034

RESUMEN

Background Cerebral folate deficiency (CFD) syndrome is characterised by a low concentration of 5-methyltetrahydrofolate in cerebrospinal fluid, while folate levels in plasma and red blood cells are in the low normal range. Mutations in several folate pathway genes, including FOLR1 (folate receptor alpha, FRα), DHFR (dihydrofolate reductase) and PCFT (proton coupled folate transporter) have been previously identified in patients with CFD. Methods In an effort to identify causal mutations for CFD, we performed whole exome sequencing analysis on eight CFD trios and identified eight de novo mutations in seven trios. Results Notably, we found a de novo stop gain mutation in the capicua (CIC) gene. Using 48 sporadic CFD samples as a validation cohort, we identified three additional rare variants in CIC that are putatively deleterious mutations. Functional analysis indicates that CIC binds to an octameric sequence in the promoter regions of folate transport genes: FOLR1, PCFT and reduced folate carrier (Slc19A1; RFC1). The CIC nonsense variant (p.R353X) downregulated FOLR1 expression in HeLa cells as well as in the induced pluripotent stem cell (iPSCs) derived from the original CFD proband. Folate binding assay demonstrated that the p.R353X variant decreased cellular binding of folic acid in cells. Conclusion This study indicates that CIC loss of function variants can contribute to the genetic aetiology of CFD through regulating FOLR1 expression. Our study described the first mutations in a non-folate pathway gene that can contribute to the aetiology of CFD.


Asunto(s)
Cerebro/metabolismo , Receptor 1 de Folato/genética , Deficiencia de Ácido Fólico/líquido cefalorraquídeo , Mutación con Pérdida de Función , Enfermedades del Sistema Nervioso/líquido cefalorraquídeo , Proteínas Represoras/genética , Tetrahidrofolatos/líquido cefalorraquídeo , Células Cultivadas , Regulación hacia Abajo , Femenino , Receptor 1 de Folato/deficiencia , Deficiencia de Ácido Fólico/genética , Células HEK293 , Humanos , Masculino , Enfermedades del Sistema Nervioso/genética , Distrofias Neuroaxonales , Linaje , Análisis de Secuencia de ADN
7.
Proc Natl Acad Sci U S A ; 115(13): 3344-3349, 2018 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-29531090

RESUMEN

Cell cycle progression is tightly regulated by cyclin-dependent kinases (CDKs). The ankyrin-repeat protein p19INK4d functions as a key regulator of G1/S transition; however, its molecular mode of action is unknown. Here, we combine cell and structural biology methods to unravel the mechanism by which p19INK4d controls cell cycle progression. We delineate how the stepwise phosphorylation of p19INK4d Ser66 and Ser76 by cell cycle-independent (p38) and -dependent protein kinases (CDK1), respectively, leads to local unfolding of the three N-terminal ankyrin repeats of p19INK4d This dissociates the CDK6-p19INK4d inhibitory complex and, thereby, activates CDK6. CDK6 triggers entry into S-phase, whereas p19INK4d is ubiquitinated and degraded. Our findings reveal how signaling-dependent p19INK4d unfolding contributes to the irreversibility of G1/S transition.


Asunto(s)
Ciclo Celular/fisiología , Inhibidor p19 de las Quinasas Dependientes de la Ciclina/química , Inhibidor p19 de las Quinasas Dependientes de la Ciclina/metabolismo , Desplegamiento Proteico , División Celular , Células HEK293 , Células HeLa , Humanos , Modelos Moleculares , Fosforilación , Conformación Proteica , Proteolisis , Transducción de Señal
8.
Nat Commun ; 8(1): 818, 2017 10 10.
Artículo en Inglés | MEDLINE | ID: mdl-29018201

RESUMEN

Transcription factor NRF2, encoded by NFE2L2, is the master regulator of defense against stress in mammalian cells. Somatic mutations of NFE2L2 leading to NRF2 accumulation promote cell survival and drug resistance in cancer cells. Here we show that the same mutations as inborn de novo mutations cause an early onset multisystem disorder with failure to thrive, immunodeficiency and neurological symptoms. NRF2 accumulation leads to widespread misregulation of gene expression and an imbalance in cytosolic redox balance. The unique combination of white matter lesions, hypohomocysteinaemia and increased G-6-P-dehydrogenase activity will facilitate early diagnosis and therapeutic intervention of this novel disorder.The NRF2 transcription factor regulates the response to stress in mammalian cells. Here, the authors show that activating mutations in NRF2, commonly found in cancer cells, are found in four patients with a multisystem disorder characterized by immunodeficiency and neurological symptoms.


Asunto(s)
Encéfalo/diagnóstico por imagen , Discapacidades del Desarrollo/genética , Insuficiencia de Crecimiento/genética , Síndromes de Inmunodeficiencia/genética , Discapacidades para el Aprendizaje/genética , Factor 2 Relacionado con NF-E2/genética , Adolescente , Sitios de Unión/genética , Niño , Femenino , Regulación de la Expresión Génica , Humanos , Lactante , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Imagen por Resonancia Magnética , Masculino , Mutación , Mutación Missense , Síndrome
9.
J Invest Dermatol ; 136(7): 1471-1478, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27033150

RESUMEN

Desmosomes mediate strong intercellular adhesion through desmosomal cadherins that interact with intracellular linker proteins including plakophilins (PKPs) 1-3 to anchor the intermediate filaments. PKPs show overlapping but distinct expression patterns in the epidermis. So far, the contribution of individual PKPs in differentially regulating desmosome function is incompletely understood. To resolve the role of PKP1 we ablated the PKP1 gene. Here, we report that PKP1(-/-) mice were born at the expected mendelian ratio with reduced birth weight, but they otherwise appeared normal immediately after birth. However, their condition rapidly declined, and the mice died within 24 hours, developing fragile skin with lesions in the absence of obvious mechanical trauma. This was accompanied by sparse and small desmosomes. Newborn PKP1(-/-) mice showed disturbed tight junctions with an impaired inside-out barrier, whereas the outside-in barrier was unaffected. Keratinocytes isolated from these mice showed strongly reduced intercellular cohesion, delayed tight junction formation, and reduced transepithelial resistance and reduced proliferation rates. Our study shows a nonredundant and essential role of PKP1 in desmosome and tight junction function and supports a role of PKP1 in growth control, a function that is crucial in wound healing and epidermal carcinogenesis.


Asunto(s)
Desmosomas/metabolismo , Epidermis/patología , Placofilinas/fisiología , Uniones Estrechas/metabolismo , Animales , Animales Recién Nacidos , Carcinogénesis , Adhesión Celular , Proliferación Celular , Epidermis/metabolismo , Ratones , Ratones Noqueados , Placofilinas/genética , Piel/metabolismo , Piel/patología , Cicatrización de Heridas
10.
Cell Commun Adhes ; 21(1): 25-42, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24460199

RESUMEN

The regulation of adhesion and growth is important for epithelial function and dysfunction. ß-catenin (armadillo in Drosophila) is the prototype of a multifunctional molecule that regulates cell adhesion via adherens junctions and cell signaling via LEF/TCF transcription factors. Desmosomal armadillo proteins comprise plakoglobin and the plakophilins 1, 2, and 3. These proteins are essential for building up the desmosome and linking the desmosomal cadherins to keratin filaments. High expression of plakophilins in desmosomes correlates with strong intercellular cohesion and is essential for tissue integrity under mechanical stress. However, like ß-catenin, these proteins have diverse non-desmosomal functions, for example, in regulating actin organization, protein synthesis, and growth control. In line with these functions, their de-regulated expression with up- as well as down-regulation has been connected to cancer and metastasis. Now, recent evidence sheds light on the post-translational regulation and provides an explanation for how de-regulation of plakophilins can contribute to cancer.


Asunto(s)
Desmosomas/metabolismo , Placofilinas/metabolismo , Animales , Adhesión Celular , Humanos , Neoplasias/metabolismo , Neoplasias/patología , Placofilinas/química , Placofilinas/genética , Transducción de Señal , beta Catenina/metabolismo , Proteínas de Unión al GTP rho/metabolismo
11.
J Cell Sci ; 126(Pt 8): 1832-44, 2013 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-23444369

RESUMEN

Downregulation of adherens junction proteins is a frequent event in carcinogenesis. How desmosomal proteins contribute to tumor formation by regulating the balance between adhesion and proliferation is not well understood. The desmosomal protein plakophilin 1 can increase intercellular adhesion by recruiting desmosomal proteins to the plasma membrane or stimulate proliferation by enhancing translation rates. Here, we show that these dual functions of plakophilin 1 are regulated by growth factor signaling. Insulin stimulation induced the phosphorylation of plakophilin 1, which correlated with reduced intercellular adhesion and an increased activity of plakophilin 1 in the stimulation of translation. Phosphorylation was mediated by Akt2 at four motifs within the plakophilin 1 N-terminal domain. A plakophilin 1 phospho-mimetic mutant revealed reduced intercellular adhesion and accumulated in the cytoplasm, where it increased translation and proliferation rates and conferred the capacity of anchorage-independent growth. The cytoplasmic accumulation was mediated by the stabilization of phosphorylated plakophilin 1, which displayed a considerably increased half-life, whereas non-phosphorylated plakophilin 1 was more rapidly degraded. Our data indicate that upon activation of growth factor signaling, plakophilin 1 switches from a desmosome-associated growth-inhibiting to a cytoplasmic proliferation-promoting function. This supports the view that the deregulation of plakophilin 1, as observed in several tumors, directly contributes to hyperproliferation and carcinogenesis in a context-dependent manner.


Asunto(s)
Adhesión Celular/fisiología , Placofilinas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Adhesión Celular/genética , Línea Celular , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular/genética , Supervivencia Celular/fisiología , Células HeLa , Humanos , Inmunoprecipitación , Insulina/metabolismo , Espectrometría de Masas , Fosforilación , Placofilinas/genética , Proteínas Proto-Oncogénicas c-akt/genética , Transducción de Señal/fisiología , Técnicas del Sistema de Dos Híbridos
12.
Cell Cycle ; 9(15): 2973-8, 2010 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-20699665

RESUMEN

Plakophilins 1-3 are members of the p120(ctn)-family of armadillo related proteins. They have been characterized as desmosomal plaque proteins, stabilizing desmosomal cadherins at the plasma membrane and interacting with the cytoskeletal linker protein desmoplakin. Loss of cell adhesion contributes to cancerogenesis. In agreement with this, some tumors were found to lack plakophilin expression. Surprisingly, in other tumors, plakophilins 1 and 3 are overexpressed. We have recently identified a function of plakophilins 1 and 3 in the regulation of protein synthesis. Plakophilin 1 was characterized as a component of the cap-binding translation initiation complex where it associates directly with the initiation factor eIF4A1. Plakophilin 1 not only stimulated the recruitment of eIF4A1 into the cap complex but also its helicase activity. This pointed to a role of plakophilin 1 in the stimulation of proliferation. Given the importance of mRNA translation and protein synthesis in the development of cancer, we speculate that overexpressed plakophilin 1 could contribute to tumor formation. Thus, plakophilin's function in cancerogenesis could go both ways: while an increase of plakophilin could support cancerogenesis via the stimulation of translation and proliferation, loss of plakophilin could contribute to cancerogenesis and/or metastasis via loss of contact inhibition and increased motility. Elucidating the regulation of plakophilin's function in adhesion versus translation will help to understand this context-dependent phenomenon.


Asunto(s)
Placofilinas/metabolismo , Biosíntesis de Proteínas , Animales , Adhesión Celular , Proliferación Celular , Humanos , Ratones , Modelos Biológicos , Neoplasias/metabolismo , Neoplasias/patología
13.
J Cell Biol ; 188(4): 463-71, 2010 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-20156963

RESUMEN

Plakophilins 1-3 (PKP1-3) are desmosomal proteins of the p120(ctn) family of armadillo-related proteins that are essential for organizing the desmosomal plaque. Recent findings identified PKPs in stress granules, suggesting an association with the translational machinery. However, a role of PKPs in controlling translation remained elusive so far. In this study, we show a direct association of PKP1 with the eukaryotic translation initiation factor 4A1 (eIF4A1). PKP1 stimulated eIF4A1-dependent translation via messenger RNA cap and encephalomyocarditis virus internal ribosomal entry site (IRES) structures, whereas eIF4A1-independent translation via hepatitis C virus IRES was not affected. PKP1 copurified with eIF4A1 in the cap complex, and its overexpression stimulated eIF4A1 recruitment into cap-binding complexes. At the molecular level, PKP1 directly promoted eIF4A1 adenosine triphosphatase activity. The stimulation of translation upon PKP1 overexpression correlated with the up-regulation of proliferation and cell size. In conclusion, these findings identify PKP1 as a regulator of translation and proliferation via modulation of eIF4A1 activity and suggest that PKP1 controls cell growth in physiological and pathological conditions.


Asunto(s)
Factor 4A Eucariótico de Iniciación/metabolismo , Placofilinas/metabolismo , Biosíntesis de Proteínas , Adenosina Trifosfatasas/metabolismo , Línea Celular , Proliferación Celular , Tamaño de la Célula , Humanos , Unión Proteica , Transporte de Proteínas , Análogos de Caperuza de ARN/metabolismo , Caperuzas de ARN/metabolismo , ARN Interferente Pequeño/metabolismo , Vesículas Secretoras/metabolismo
14.
Cell Cycle ; 6(2): 122-7, 2007 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-17264675

RESUMEN

P120(ctn) is the prototype of a subfamily of armadillo proteins that also comprises p0071, delta-catenin, ARVCF and the more distantly related plakophilins 1-3. These proteins have well established roles in regulating adherens junction and desmosome formation which critically depends on their capacity to cluster cadherins. Besides this function in cell adhesion that is mediated by a membrane associated pool, these proteins also show cytoplasmic and nuclear localization. While their nuclear function is still enigmatic, major progress in understanding their cytoplasmic role has been made. In the cytoplasm, the p120 catenins appear responsible for the spatio-temporal control of small Rho-GTPases in various cellular contexts. Whereas p120(ctn) has a major function in regulating cell adhesion and motility through controlling Rho-GTPases, a recent report shows that the closely related protein p0071 associates and regulates RhoA at the cleavage furrow during cytokinesis. Overexpression and knockdown of p0071 induced a cytokinesis defect that was mediated by up- or downregulation of RhoA activity at the contractile ring. There, p0071 interacted directly with RhoA itself and with the Rho-GEF Ect2. Full activation of RhoA required Ect2 as well as p0071 indicating that these two proteins act in conjunction to regulate RhoA during cytokinesis. Here we discuss the function of p120 catenins as versatile scaffolds that confer specificity to the complex regulation of Rho-GTPases. By controlling numerous stimulating guanine exchange factors (GEFs) and inhibiting GTPase activating proteins (GAPs) via the formation of multiprotein complexes at the right time and place, they direct the spatio-temporal control of Rho-signalling.


Asunto(s)
Moléculas de Adhesión Celular/fisiología , Citocinesis/fisiología , Fosfoproteínas/fisiología , Placofilinas/fisiología , Proteína de Unión al GTP rhoA/metabolismo , Animales , Cateninas , Adhesión Celular/fisiología , Moléculas de Adhesión Celular/química , Humanos , Fosfoproteínas/química , Placofilinas/química , Transducción de Señal/fisiología , Proteína de Unión al GTP rhoA/química , Catenina delta
15.
Nat Cell Biol ; 8(12): 1432-40, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17115030

RESUMEN

Cytokinesis requires the spatio-temporal coordination of cell-cycle control and cytoskeletal reorganization. Members of the Rho-family of GTPases are crucial regulators of this process and assembly of the contractile ring depends on local activation of Rho signalling. Here, we show that the armadillo protein p0071, unlike its relative p120(ctn), is localized at the midbody during cytokinesis and is essential for cell division. Both knockdown and overexpression of p0071 interfered with normal cell growth and survival due to cytokinesis defects with formation of multinucleated cells and induction of apoptosis. This failure of cytokinesis seemingly correlated with the deregulation of Rho activity in response to altered p0071 expression. The function of p0071 in regulating Rho activity occurred through an association of p0071 with RhoA, as well as the physical and functional interaction of p0071 with Ect2, the one Rho guanine-nucleotide exchange factor (GEF) essential for cytokinesis. These findings support an essential role for p0071 in spatially regulating restricted Rho signalling during cytokinesis.


Asunto(s)
Proteínas del Dominio Armadillo/metabolismo , Citocinesis , Placofilinas/metabolismo , Transducción de Señal , Proteína de Unión al GTP rhoA/metabolismo , Animales , Centrosoma/metabolismo , Regulación hacia Abajo , Humanos , Ratones , Células 3T3 NIH , Unión Proteica , Proteínas Proto-Oncogénicas/metabolismo , Interferencia de ARN , Huso Acromático/metabolismo
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